Study: All Modern Humans Descended From Small Tribe 70 000 Years Ago

A story making its way around the news wires, states that evidence of incredible homogeneity in modern humans has come to light. According to the story by Richard Gray:

Dr Peter Forster, a senior lecturer in archaeogenetics at Anglia Ruskin University in Cambridge who carried out some of the genetic work, said: "The founder populations cannot have been very big. We are talking about just a few hundred individuals."

Homo sapiens, known casually as "modern humans", are thought to have first evolved around 195,000 years ago in east Africa – the earliest remains from that time were uncovered near the Omo River in Ethiopia.

It is thought that by 150,000 years ago these early modern humans had managed to spread to other parts of Africa and fossilised remains have been found on the Cape of Good Hope in South Africa.

My gut reaction to this (without any empirical data, mind you) is that, like the original MtDNA research that was done in the late 1980s by Cann, Stoneking and Wilson, there will prove to be holes in the study. Aside from this, I can think of a few things that would make this not as clear-cut a case as it seems. For starters, What about the clearly modern humans that were in place in the Near East around 100-110 ky BP at the sites of Skhul and Qafzeh? Did these newcomers not interbreed with them? Did this population really "fail" as the story relates? Modern modern humans seem to survive just fine when conditions dry out. On the other hand, John Shea suggests that a similar conclusion may be inferred:

Absent archaeological evidence for a migration of early modern humans out of Africa during the Early MP, the presence of early modern humans ca. 80–130 Kyr, suggests that the Levant was part of a broader region of modern human origins and initial dispersal that encompassed much of Africa. The recent discovery of somewhat older early modern humans at Herto in the MiddleAwashValley, Ethiopia (White et al., 2003), and better dating of the Omo Kibish fossils (Leakey et al., 1969; Shea et al., 2002) will doubtless clarify the evolutionary relationships between African and Levantine late Middle Pleistocene human populations. It is important that we keep an open mind about continuity between the Skhul/Qafzeh humans and later Levantine populations. The gap in the Levantine record for modern humans’ presence in region between 40 and 80Kyr could indicate that the Skhul/Qafzeh humans were an evolutionary dead end with no post-MP descendants (Shea, 2003a, p. 181). The UP human populations of the Levant and Europe may be descended from modern human populations who arrived in the Levant after 40–50 Kyr.¹

I will be curious to read the study when it comes out.

¹Shea, J. (2003) The Middle Paleolithic of the East Mediterranean Levant. Journal of World Prehistory. 17(4): 313-394